The Coastguard is helping in the search for missing student Libby Squire, which is now entering its fourth day.
The University of Hull student hasn't been seen since vanishing from Hull's Beverley Road on Thursday night.
Police dogs have been deployed around the area where she was last spotted.
Speaking yesterday, Detective Superintendent Simon Gawthorpe said: "There are a number of leads we are following up and I want to offer my thanks to everyone who has come forward with information, your help has been invaluable.
"We're trying to trace Libby’s steps and piece together her movements that night. We know she got into a taxi outside the Welly Club on Beverley Road at around 11pm on Thursday, 31st January.
"Libby got out of the taxi a short while later near her home address on Wellesley Avenue, but was later seen on CCTV on Beverley Road, close to the junction with Haworth Street at around 11.45pm.
"We're keen to speak to anyone who may have been on Haworth Street, which is almost adjacent to Beresford Avenue, between 11.30pm and 12.30am as part of this line of enquiry, to understand Libby's movements that night.
"Officers will be conducting further house to house enquiries in the Beresford Avenue area, Haworth Street and around Beverley Road today and special constables will be out on patrol in the areas.
"We have specialist teams again out today carrying out searches and we are working with Humberside Fire and Rescue and the Coastguard, who will be around the River Hull.
"I completely understand people will want to help with the searches, but I would please ask that you instead continue to help us by coming forward with any information, no matter how small or insignificant you think it may be, as it could link together with information we already have and help us to find Libby.
"We need your help with information to piece together Libby’s movements, to find her and return her home safely to her family."